In ClearOS, we need to bind to specific interfaces (e.g. Squid, CUPS) more than a typical Linux distribution. Many upstream systemd scripts contain this directive:

[Unit]
...
After=network.target

The problem: there's no guarantee that the network has bind-able interfaces when the "network.target" event occurs. Since we don't want to patch a bunch of upstream systemd scripts, create an "onboot" event as a workaround. Any app that needs to bind to specific IPs should have a sanity check script added to /var/clearos/events/onboot.